/*********************************************************************
 * Copyright (C) 2002 Andrew Khan
 * <p>
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 * <p>
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 * <p>
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 ***************************************************************************/

package jxl.biff.formula;

import jxl.Cell;
import jxl.biff.CellReferenceHelper;
import jxl.biff.IntegerHelper;

/**
 * A cell reference in a formula
 */
class SharedFormulaArea extends Operand implements ParsedThing {
    private int columnFirst;
    private int rowFirst;
    private int columnLast;
    private int rowLast;

    private boolean columnFirstRelative;
    private boolean rowFirstRelative;
    private boolean columnLastRelative;
    private boolean rowLastRelative;

    /**
     * The cell containing the formula.  Stored in order to determine
     * relative cell values
     */
    private Cell relativeTo;

    /**
     * Constructor
     *
     * @param the cell the formula is relative to
     */
    public SharedFormulaArea(Cell rt) {
        relativeTo = rt;
    }

    int getFirstColumn() {
        return columnFirst;
    }

    int getFirstRow() {
        return rowFirst;
    }

    int getLastColumn() {
        return columnLast;
    }

    int getLastRow() {
        return rowLast;
    }

    /**
     * Reads the ptg data from the array starting at the specified position
     *
     * @param data the RPN array
     * @param pos the current position in the array, excluding the ptg identifier
     * @return the number of bytes read
     */
    public int read(byte[] data, int pos) {
        // Preserve signage on column and row values, because they will
        // probably be relative

        rowFirst = IntegerHelper.getShort(data[pos], data[pos + 1]);
        rowLast = IntegerHelper.getShort(data[pos + 2], data[pos + 3]);

        int columnMask = IntegerHelper.getInt(data[pos + 4], data[pos + 5]);
        columnFirst = columnMask & 0x00ff;
        columnFirstRelative = ((columnMask & 0x4000) != 0);
        rowFirstRelative = ((columnMask & 0x8000) != 0);

        if (columnFirstRelative) {
            columnFirst = relativeTo.getColumn() + columnFirst;
        }

        if (rowFirstRelative) {
            rowFirst = relativeTo.getRow() + rowFirst;
        }

        columnMask = IntegerHelper.getInt(data[pos + 6], data[pos + 7]);
        columnLast = columnMask & 0x00ff;

        columnLastRelative = ((columnMask & 0x4000) != 0);
        rowLastRelative = ((columnMask & 0x8000) != 0);

        if (columnLastRelative) {
            columnLast = relativeTo.getColumn() + columnLast;
        }

        if (rowLastRelative) {
            rowLast = relativeTo.getRow() + rowLast;
        }


        return 8;
    }

    public void getString(StringBuffer buf) {
        CellReferenceHelper.getCellReference(columnFirst, rowFirst, buf);
        buf.append(':');
        CellReferenceHelper.getCellReference(columnLast, rowLast, buf);
    }

    /**
     * Gets the token representation of this item in RPN
     *
     * @return the bytes applicable to this formula
     */
    byte[] getBytes() {
        byte[] data = new byte[9];
        data[0] = Token.AREA.getCode();

        // Use absolute references for columns, so don't bother about
        // the col relative/row relative bits
        IntegerHelper.getTwoBytes(rowFirst, data, 1);
        IntegerHelper.getTwoBytes(rowLast, data, 3);
        IntegerHelper.getTwoBytes(columnFirst, data, 5);
        IntegerHelper.getTwoBytes(columnLast, data, 7);

        return data;
    }

    /**
     * If this formula was on an imported sheet, check that
     * cell references to another sheet are warned appropriately
     * Does nothing
     */
    void handleImportedCellReferences() {
    }

}



